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A. C. Larson, B. I. Gaynes, M. Rosenberg, J. Rubestein, Z. Ai, L. Renambot, B. Tazioli; A Novel Computer-Based Software System to Visualize in vivo Human Lens Morphology and Density Based on Scheimpflug Photographs. Invest. Ophthalmol. Vis. Sci. 2008;49(13):4013. doi: https://doi.org/.
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© ARVO (1962-2015); The Authors (2016-present)
1) assess the utility of the PentacamTM Scheimpflug camera as a model for studying clinical correlates of lens morphology in vivo compared to conventional slit-lamp photography and 2) describe the correlation between contrast sensitivity and objective measure of lens density among adults with functionally transparent crystalline lenses.
Study design was of a cross-sectional assessment of adults, age 18-60, with functionally transparent lenses without evidence of ocular disease. All subjects demonstrated 20/20 or better visual acuity measured monocularly. The PentacamTM, a proprietary rotating Scheimpflug camera, was used for this study. In one, two-second scan, the device captures fifty, 2-D photographs of the eye by rotating the camera about the optical axis. In the same scan, the PentacamTM provides measures of media density based on integrative analysis of a pre-programmed database. Contrast detection was assessed by use of Peli-Robson charts. Using a computer program written by the investigators, the Scheimpflug photos were combined to create a 3-D volumetric data set that was viewed in stereo using 3-D glasses.
Nuclear and cortical lens density were found to be highly correlative (Spearmen r = 0.6294, p = 0.009) while contrast sensitivity was found to be inversely related to both nuclear and cortical lens density (r = -0.6381 and -0.6107 respectively, p < 0.01). In a linear regression model, objective determination of either nuclear or cortical lens density accurately predicted loss of contrast sensitivity independently. Integration of the Scheimpflug images into the developed software system resulted in accurate 3-dimensional re-creation of lens morphology.
Objective assessment of lens density is correlative with contrast sensitivity and appears unrelated to visual acuity. 3-D visualization of the lens provides meaningful study of in-vivo lens morphology and may be exploited clinically as an adjunct to slit lamp biomicroscopy. Two improvements were recommended. First, higher Scheimpflug photo resolution would allow for zoom and more intricate linear and angular measurements of the sutures. Second, more images captured within the 180-degree scan would allow for more intricate study of suture geometry.
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